ABSTRACT Distinct premalignant lesions of the lung are known precursors of lung squamous cell carcinoma (LUSC) and adenocarcinoma (LUAD), the most common subtypes of lung cancer. Currently it is difficult to predict which of these lesions will progress to invasive cancer and an incomplete understanding of their biology limits our ability to develop interventions that can prevent this progression. The Lung Pre-Cancer Atlas (PCA) will access extensive banks of longitudinal and cross-sectional specimens of premalignant lesions (PMLs) available within our network of medical centers in our Lung PCA Biospecimen Unit. These centers have long-standing programs that have studied these pre-cancerous lesions, and have the staff and infrastructure to carry out the primary goals of the Biospecimen Unit. As specimen samples are often limited, the success of the PCA will depend on our Unit's capability to optimize tissue processing protocols. Studies performed at the central processing core sites of the Biospecimen Unit (University of Colorado, MD Anderson Cancer Center, and University College of London) have established methods for preparing high-yield, high-quality nucleic acids, tissue sections and other specimen types from LUSC and LUAD pre-cancers. In Phase 1, we will utilize our existing tissue banks to build retrospective pre-cancer cohorts that will be used to standardize specimen processing and optimize newly emerging techniques to support the genetic, molecular, and cellular assays to be employed in the Characterization Unit. In Phase 2, the Biospecimen Unit will recruit patients at high risk for developing invasive lung cancer into our prospective pre-cancer cohorts from our prior established studies. Importantly, we will establish a longitudinal LUSC cohort where airway PMLs are sampled repeatedly over a 2- year period as they progress towards or regress away from LUSC. We will enrich this cohort for patients at higher risk for progression of PMLs to invasive cancer by identifying those with features such as persistent PMLs, which we have shown to be associated with a nearly 8-fold increase in risk for development of invasive LUSC. Enrichment of the prospective cross-sectional LUAD pre-cancer cohort will be accomplished via the use of a radiographic algorithm in the lung cancer screening setting that can increase the yield of finding pre- cancer lesions within the lung parenchyma. Finally, the Biospecimen Unit will include an expert staff to establish a robust clinical database that will include an image-based mapping tool to facilitate identification of the best specimens for analyses and support future users of the Lung PCA. Investigators of the Biospecimen Unit have multiple decades of experience in the study of premalignant lung lesions that will provide expertise to collect, annotate, and build a repository necessary to construct a searchable, multidimensional Lung PCA that clinicians will be able to employ to identify patients at high risk for invasive cancer in the future.